Project Summary/Abstract The goal of this consortium is to establish tools that can be used as biomarkers and/or sensitive and reliable objective assays of social impairment in autism spectrum disorder (ASD) clinical trials. The consortium will conduct a naturalistic, longitudinal study of preschool (3-5 years) and school aged (6-11 years) children with ASD and typical development (TD) with IQ ranging from 50-115. Children will be assessed across three time points (T1: Baseline, T2: 6 weeks, T3: 24 weeks) using clinician, caregiver and lab-based (LB) measures of social impairment, along with a battery of conceptually related EEG and ET tasks and independent ratings of clinical status. Five Collaborating Implementation Sites (?Sites?), all highly experienced in multi-site collaborative clinical research using the methodologies proposed here in children with TD and ASD, will contribute equally to data collection. The Data Coordinating Core (DCC) will provide a secure informatics infrastructure to streamline communication and data flow throughout the consortium to ensure organized, secure data management, quality control, and reliable upload to the National Database for Autism Research (NDAR) and NIH/NIMH Data Repositories. The Data Acquisition and Analysis Core (DAAC) will oversee consistent application of scientific standards and methodological rigor for data collection, processing, and analytics. The Administrative Core (Admin Core) will oversee the operations of the Sites, the DCC, and the DAAC to ensure methodologically and ethically rigorous, efficient completion of study aims and to coordinate with federal and private partners in this cooperative agreement. The specific aims of the Admin Core are to: 1) Coordinate and streamline communication and data sharing among components of the consortium to manage all aspects of the Set up, Implementation and Data Analysis phases, including recruitment and data collection, data management and quality control, standardization of data acquisition and processing, analytic planning, financial management; 2) Administer the consortium project across all Sites and Cores in terms of managing the central IRB, developing and disseminating SOPs, implementing GCP, maintaining research fidelity, overseeing quality control, and planning timely upload to NIH/NIMH Data Repositories; 3) Maintain appropriate communication among the consortium members by integrating feedback from federal and private partners, executing the finalized protocol as per the collaborative agreement, bringing together consortium leaders and partners in Steering Committee Meetings, and convening meetings of the External Advisory Board.